+
+int send_one_fd(int transport_fd, int fd, int flags) {
+ union {
+ struct cmsghdr cmsghdr;
+ uint8_t buf[CMSG_SPACE(sizeof(int))];
+ } control = {};
+ struct msghdr mh = {
+ .msg_control = &control,
+ .msg_controllen = sizeof(control),
+ };
+ struct cmsghdr *cmsg;
+
+ assert(transport_fd >= 0);
+ assert(fd >= 0);
+
+ cmsg = CMSG_FIRSTHDR(&mh);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+ memcpy(CMSG_DATA(cmsg), &fd, sizeof(int));
+
+ mh.msg_controllen = CMSG_SPACE(sizeof(int));
+ if (sendmsg(transport_fd, &mh, MSG_NOSIGNAL | flags) < 0)
+ return -errno;
+
+ return 0;
+}
+
+/// UNNEEDED by elogind
+#if 0
+int receive_one_fd(int transport_fd, int flags) {
+ union {
+ struct cmsghdr cmsghdr;
+ uint8_t buf[CMSG_SPACE(sizeof(int))];
+ } control = {};
+ struct msghdr mh = {
+ .msg_control = &control,
+ .msg_controllen = sizeof(control),
+ };
+ struct cmsghdr *cmsg, *found = NULL;
+
+ assert(transport_fd >= 0);
+
+ /*
+ * Receive a single FD via @transport_fd. We don't care for
+ * the transport-type. We retrieve a single FD at most, so for
+ * packet-based transports, the caller must ensure to send
+ * only a single FD per packet. This is best used in
+ * combination with send_one_fd().
+ */
+
+ if (recvmsg(transport_fd, &mh, MSG_NOSIGNAL | MSG_CMSG_CLOEXEC | flags) < 0)
+ return -errno;
+
+ CMSG_FOREACH(cmsg, &mh) {
+ if (cmsg->cmsg_level == SOL_SOCKET &&
+ cmsg->cmsg_type == SCM_RIGHTS &&
+ cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
+ assert(!found);
+ found = cmsg;
+ break;
+ }
+ }
+
+ if (!found) {
+ cmsg_close_all(&mh);
+ return -EIO;
+ }
+
+ return *(int*) CMSG_DATA(found);
+}
+
+void nop_signal_handler(int sig) {
+ /* nothing here */
+}
+#endif // 0
+
+int version(void) {
+ puts(PACKAGE_STRING "\n"
+ SYSTEMD_FEATURES);
+ return 0;
+}
+
+/// UNNEEDED by elogind
+#if 0
+bool fdname_is_valid(const char *s) {
+ const char *p;
+
+ /* Validates a name for $LISTEN_FDNAMES. We basically allow
+ * everything ASCII that's not a control character. Also, as
+ * special exception the ":" character is not allowed, as we
+ * use that as field separator in $LISTEN_FDNAMES.
+ *
+ * Note that the empty string is explicitly allowed
+ * here. However, we limit the length of the names to 255
+ * characters. */
+
+ if (!s)
+ return false;
+
+ for (p = s; *p; p++) {
+ if (*p < ' ')
+ return false;
+ if (*p >= 127)
+ return false;
+ if (*p == ':')
+ return false;
+ }
+
+ return p - s < 256;
+}
+#endif // 0